memory_debugging.h

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/* Copyright (c) 2017, 2024, Oracle and/or its affiliates.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.
 
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   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
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   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License, version 2.0, for more details.
 
   You should have received a copy of the GNU General Public License
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   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
#ifndef MEMORY_DEBUGGING_INCLUDED
#define MEMORY_DEBUGGING_INCLUDED
 
/**
  @file memory_debugging.h
 
  Various macros useful for communicating with memory debuggers,
  such as Valgrind.
*/
 
#include <string.h>
 
#ifdef HAVE_VALGRIND
#include <valgrind/valgrind.h>
 
#define MEM_MALLOCLIKE_BLOCK(p1, p2, p3, p4) \
  VALGRIND_MALLOCLIKE_BLOCK(p1, p2, p3, p4)
#define MEM_FREELIKE_BLOCK(p1, p2) VALGRIND_FREELIKE_BLOCK(p1, p2)
#include <valgrind/memcheck.h>
 
#define MEM_UNDEFINED(a, len) VALGRIND_MAKE_MEM_UNDEFINED(a, len)
#define MEM_DEFINED_IF_ADDRESSABLE(a, len) \
  VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE(a, len)
#define MEM_NOACCESS(a, len) VALGRIND_MAKE_MEM_NOACCESS(a, len)
#define MEM_CHECK_ADDRESSABLE(a, len) VALGRIND_CHECK_MEM_IS_ADDRESSABLE(a, len)
 
#else /* HAVE_VALGRIND */
 
#define MEM_MALLOCLIKE_BLOCK(p1, p2, p3, p4) \
  do {                                       \
  } while (0)
#define MEM_FREELIKE_BLOCK(p1, p2) \
  do {                             \
  } while (0)
#define MEM_UNDEFINED(a, len) ((void)0)
#define MEM_DEFINED_IF_ADDRESSABLE(a, len) ((void)0)
#define MEM_NOACCESS(a, len) ((void)0)
#define MEM_CHECK_ADDRESSABLE(a, len) ((void)0)
 
#endif
 
#if !defined(NDEBUG) || defined(HAVE_VALGRIND)
 
/**
  Put bad content in memory to be sure it will segfault if dereferenced.
  With Valgrind, verify that memory is addressable, and mark it undefined.
*/
inline void TRASH(void *ptr, size_t length) {
  MEM_CHECK_ADDRESSABLE(ptr, length);
  memset(ptr, 0x8F, length);
  MEM_UNDEFINED(ptr, length);
}
 
#else
 
inline void TRASH(void *, size_t) {}
 
#endif
 
#endif  // MEMORY_DEBUGGING_INCLUDED